Internet Protocol Multicast with Internet Protocol Unicast/Multicast Error Correction

1. A method of delivering digital information, comprising: sending a segment to a multicast group; receiving a set of error notifications indicating incomplete receipt of the segment from a subset of clients of the multicast group, wherein a number of clients in the subset of clients of the multicast group is greater than a predefined minimum of clients; determining to resend at least a portion of the segment to a subset of the multicast group based on a number of error notifications received; and resending the at least a portion of the segment to the subset of the multicast group.

2. The method of claim 1 wherein the subset of the multicast group is the complete multicast group.

3. The method of claim 1 wherein the subset of clients is greater than a predefined percentage of the multicast group.

4. The method of claim 1 further comprising: sending a second segment to the multicast group; receiving a second set of error notifications indicating incomplete receipt of the second segment from a second subset of clients of the multicast group; determining to send at least a portion of the second segment using Internet Protocol unicast to each of the second subset of clients based on the number of error notifications received; establishing an Internet Protocol unicast connection to each of the second subset of clients; and sending the at least a portion of the second segment to each of the second subset of clients through the respective Internet Protocol unicast connection.

5. The method of claim 4 wherein the Internet Protocol unicast connection is a Transmission Control Protocol connection.

6. The method of claim 5 wherein the subset of clients is less than a predefined percentage of the multicast group and the number of clients in the subset of clients is less than a predefined minimum of clients.

7. The method of claim 4 wherein the digital information includes a digital movie for digital cinema.

8. The method of claim 4 further comprising determining a retransmit order based on a policy.

9. The method of claim 4 wherein the policy includes one of remaining within a maximum link bandwidth limit, not retransmitting a segment to an endpoint after a predetermined number of tries, not retransmitting a segment to an endpoint determined to be unavailable, prioritizing clients, minimizing network costs, and ensuring on-time delivery.

10. The method of claim 1 further comprising: sending a second segment to the multicast group; receiving a second set of error notifications indicating incomplete receipt of the second segment from a second subset of clients of the multicast group; establishing a second multicast group including the second subset of clients; and sending at least a portion of the second segment to the second multicast group.

11. The method of claim 10 further comprising determining that the second subset of clients belong to one of a common branch of a multicast tree, a common geographic region, and a common autonomous system.

12. A method of delivering digital information, comprising: sending a segment to a multicast group; receiving a set of packet error notifications indicating incomplete receipt of the segment from a subset of clients of the multicast group; establishing a second multicast group including the subset of clients, wherein the number of clients in the second multicast group is greater than a predefined minimum of clients; and sending at least a portion of the segment to the second multicast group.

13. The method of claim 12 further comprising determining that the second subset of clients belong to one of a common branch of a multicast tree, a common geographic region, and a common autonomous system.

14. The method of claim 12 wherein the digital information includes a digital movie for digital cinema.

15. A method of delivering digital information, comprising: sending a segment to a multicast group; receiving error notifications from a subset of clients of the multicast group; determining to send at least a portion of the segment using Internet Protocol unicast to each of the subset of clients based on a number of error notifications received wherein the number of clients in the subset of clients of the multicast group is greater than a predefined minimum of clients; establishing an Internet Protocol unicast connection to each of the subset of clients; and sending the at least a portion of the segment to each of the subset of clients using the respective Internet Protocol unicast connections.

16. The method of claim 15 wherein the Internet Protocol unicast connection is a Transmission Control Protocol connection.

17. The method of claim 15 wherein the digital information includes a digital movie for digital cinema.

18. A method of delivering digital information, comprising: joining a multicast group; determining a transmission error has occurred resulting in an incomplete first segment directed to the multicast group; sending an error notification to the server requesting retransmission of at least a portion of the incomplete first segment; receiving a multicast retransmission of the at least a portion of the incomplete first segment; determining a transmission error has occurred resulting in an incomplete second segment directed to the multicast group; sending an error notification to the server requesting retransmission of at least a portion of the incomplete second segment; and receiving a unicast retransmission of the at least a portion of the incomplete second segment.

19. The method of claim 18 wherein the digital information includes a digital movie for digital cinema.